The invention relates to a process for thermal treatment, especially a cooling, of at least one continuously running thread plug, as formed from synthetic filaments, e.g. polyamide, polyester or polyolefin filaments, in a stuffer crimping box. The thread plug is conducted over an air-permeable surface during the thermal treatment, and is then disentangled to draw off the crimped and thermally treated thread. The invention also relates to useful and improved apparatus for carrying out the process.
Such apparatus for the thermal treatment of the stuffer box thread plug preferably consists of a rotationally driven, air-permeable drum onto which one or more thread plugs are conducted and wound or coiled into a closed layer of several thread plug windings extending in helical lines around the circumference of the drum and being axially advanced by an advancing device at the entry or rear end of the drum where axial pressure is applied to the first winding. This apparatus has been proposed in U.S. Pat. No. 4,118,843 for the purpose of carrying out a special continuously operated spin-stretch texturizing process with a continuous stuffer box crimping followed by a thermal gas treatment of the continuous thread plug.
The thread plug windings which are helically coiled or wound onto the substantially cylindrical treatment drum are taken off at the exit or front end of the drum after the thermal treatment is completed, in particular, after fixing of the crimp in the filaments and usually cooling of the thread material with a gas or vapor during a sufficient residence time on the drum. The thread is thus disentangled and removed by a draw-off spooling or winding arrangement driven at a selected speed with an adjustable thread tension. In this operation, the thread plug may be slightly opened or loosened in its consistency as it is applied onto the drum in order to improve its gas-permeability on the drum. However, after the thermal treatment, the thread plug is disentangled near the exit end of the drum, and a texturized thread is drawn off at a speed which is less than the circumferential speed of the preceding stretch godets, but very much higher than the circumferential speed of the treatment drum.
Because the present invention represents a specific improvement in the process and apparatus of U.S. Pat. No. 4,118,843, being readily adapted to the embodiments and variations of treating a stuffer crimped thread plug as taught therein, this earlier and commonly assigned patent is incorporated herein by reference as fully as if set forth in its entirety.